package lab02.test28;

import java.util.Scanner;

public class Test {    public static void main(String[] args) {
    final double PI = 3.1415926;
    Scanner sc = new Scanner(System.in);
    System.out.println("请输入一个为double类型圆的半径)");
    try {
        double radius = sc.nextDouble();
        System.out.println("圆面积:" + PI * radius * radius);
    } catch (Exception e) {
        System.out.println("输入有误，请重新输入");
    }
}

}
